Continuously variable change speed gear



Oct. 22, 1935. v J. RRAMEN 2,018,533

CONTINUOUSLY VARIABLE CHANGE SPEED GEAR 'Filed Nov. 30, 1934 4 Sheets-Sheet 1,

INVENTOR 0 WM Oct. 22, 1935, J. R. RAMIN 2,013,533

7 CONTINUOUSLY VARIABLE CHANGE SPEED GEAR I Filed Nov. 30, 1934 7 4 Sheets-Sheet 2 IINVEINTOR Oct. 22, 1935. J. R. RAMIN CONTINUOUSLY VARIABLE CHANGE SPEED GEAR Filed Nov. 30. 1934 4 Sheets-Sheet s I l4 [1 I] I I l g i 4 I] i4- 5 1:5

' \NVENTOR J. R. RAMHN CQNTINUOUSLY VARIABLE CHANGE SPEED GEAR Oct. 22, 1935.

4 Sheets-Sheet 4 Filed Nov. 30, 1934 Patented Oct. 22, 1935 UNITED STATES CONTINUOUSLY VARIABLE CHANGE SPEED GEAR Jean Robert Ramin, Paris, France Application November 30, 1934, Serial No. 755,320 In France December 14, 1933 I 7 Claims.

The object of the present invention is a change speed gear in which the simple movement of a control lever will give continuous variation of the speed ratio of the primary to the secondary shaft ,between limiting values which may even be greater than 1 (speed step-up) and less than (reverse drive).

The invention consists essentially in the application to such a change speed gear of the princi- ;-,;ple which has been discovered that if a circle is o rotating about its center (primary movement) and has at the same time a movement of rotation about a point away from its center (secondary movement), the ratio between the angular yelocities of these two movements is uniquely determined at every instant by the direction of the resultant movement of the said circle at any fixed point taken in its plane, It can be proved infact that this ratio is equal to the ratio which ,;;the length of the straightline joining the two centers of rotation bears to the intercept on the same straight line between the center of the circle and the perpendicular erected at the said fixed point to the resultant direction of movement of the circle at that point. The velocity ratio of the primary and secondary movements thus remains constant for any particular direction of this resultant movement, so that to make this ratio variable in any desired manner it will asgbe sufficient to modify the said direction in a suitable Way, say by altering the position of the point at which the perpendicular just referred to intersects the straight line joining the centers.

The invention may be put into practice. by 'silrneans of a disc connected to the primary shaft by a suitable universal joint arrangement and so mounted that it can rotate about its axis on a second disc coaxial with it and fixed excentrically on the secondary shaft. The first disc is 40* guide'd in its movement by ball bearings contacting by means of their outer races with one of its faces andapplied to this face by a component of force making an angle with the normal to the plane of this face less than the angle of fric- 'tion of the outer race on the said face, so that this disc can only move in the direction defined by the planes of the bearings. Each of these bearings is capable of being angularly displaced about a straight line constituted by the intersection of its plane of rotation with a plane laid through its diameter and perpendicular to, the face of the disc with which its outer race contacts. This angular displacement provides means l O1 modifying the orientation of the bearings so that any desired variations of speed ratio can be obtained.

The invention will be better understood by means of the following description with reference to the accompanying drawings, which show by way of example one of the possible embodiments of the invention and a modification.

In the drawings Figures 1 and 2 are diagrams intended to explain the principle of the invention,

Figure 3 is an axial vertical section through a change speed gear in accordance with the invention.

Figures 4 and 5 are transverse sections of the same taken on the lines IV-IV and V-V of Figure 3 respectively and viewed in opposite directions as shown by the arrows,

Figure 6 is a partial horizontal section on the line VI-VI of Figure 3,

Figures '7 and 8 are a sectional elevation and end elevation respectively of a modified mounting of the bearings for guiding the disc.

Referring to Figure 1, let a circle 0 rotate in its own plane about its center 01 at an angular velocity 91 (primary), while the center 01 itself rotates about a point 02 at an angular velocity 92 (secondary, so that where K has a constant value.

Let A be a fixed point in the plane of the circle O. The constant length 02 01 Will be called r and the variable length 01A will be called p.

When the circle 0 has rotated about 01 through an infinitesimal angle on, the straight line O2 01 will then have turned through an angle to: about 02, and the point of the circle 0 which was originally located at A will have moved to C, the straight line AC being the resultant of the two displacements AF=w2T and FC-:w1p.

Conversely, if the surface of the circle 0 is moving at the point A in a direction AC, theratio K between the primary and secondary angular velocities can be obtained from this direction. It is easy to show that this direction AC is perpendicular to the straight line joining the point A to a point Q situated on the straight line 0 01 such that no In fact, if the straight line AD is drawn perpendicular to AC2 at A, the straight line BF parallel to AD through F and the straight line CE perpendicular to BF from C, and if the values 01' the angles are written CFE= a,CAD=B and AFB= one may write and AD=FE+BF=a cos a-i-u r cos 'y;

sin 1' sin V whence tan tan B= ular to AC2 from O1 and Q and a straight line QN perpendicular to 01M from Q, it is possible to replace the elements on the right hand side of the above equation by their equivalents in Figure 2 and to Write:

Consequently the angle QAP=B= the angle CAD, and since AD is perpendicular to AP by construction, AQ must also be perpendicular to The position of the point Q on the line 0201 obtained by erecting AQ perpendicular to AC at A accordingly determines the ratio of angular ve-- locities V 7 and thus to obtain a variation of this ratio it is only necessary to make a corresponding variation of the position of'the point Q along this line.

The arrangement shown in the figures from 3 onwards represents a practical application of the principles just expounded to the construction of Ira continuously variable speed gear between a primary and a secondary shaft mounted in line.

'In Figure 3, I is the primary shaft and 2 the secondary shaft journaled respectively in two parallel end plates 3 and 4 integral with a fixed structure 5. The common axis of rotation of the '55' two shafts corresponds to the point 02 of Figure 1. The primary shaft 1 communicates its movement by means of two universal joints 6, 1 and a cross-shaped member 8 to an annular disc 9 corresponding to the circle 0 of Figure 1. The disc 9 rotates by means of ball bearings I0, Ina

'on a disc Ii excentrically fixed to the secondary The center of the disc ll corresponds (The universal joints 6, I could shaft 2. to the point 01.

' clearly be replaced by any equivalent connection,

such as a Cardan shaft or an Oldham joint.)

On the end plate 4 are pivoted symmetrically V in relation to the secondary shaft arms l2, four in number in the present example, carrying rods i3 which latter are freely rotatable about their longitudinal axes in the arms i2. Each rod l3 has on itsouter end a ball bearing M of which the outer race contacts with the disc 9 The plane of rotation of each of these hearings is slightly oblique to the disc 9, and springs [5 attached to the structure 5 act on the arms l2 so as bearing I! if it were to move away from the cen- 1o 7 ter of the system; it can therefore only move in the direction defined by the planes of the bear- .ings and their points of contact with the disc can be considered severally equivalent to the point A of Figure 1. II The direction so defined and corresponding to AC of Figure 1 is here determined by means of pairs of guides 16, each pair being integral with one of the rods i3 and perpendicular to the line of intersection of the plane of the corresponding I bearing M with the plane of the disc 9. These 1 guides I6 embrace a movable cylinder I1, the axis of which is in the plane passing through the axes O1 and O2 and corresponds to the point Q of Figure l. excentric disc II by slide rails I811, I812 parallel i to the plane passing through the two axes O1 and O2, and it can slide along these rails to correspond with the displacement of the point Q along the straight line 0: 01. Q coincides with 0: in Figure 1 the speed ratio between the primary and secondary movements is equal to 1. It will be seen that in this case the whole system in the construction described rotates about the axis 0:, giving the equivalent ll of a direct drive. When Q coincides with 01 the ratio K is equal to O1 and the disc 9 rotates about the disc ll without producing any driving effect on the secondary shaft. When Q is between 02 and 01 the speed ratio is less than I unity, that is, the arrangement is a step-down speed gear. This ratio becomes greater than unity when Q is outside 02 O1 and beyond 02 and r then the speed is stepped up. If on the other hand the point Q is beyond 01 then the ratio is I negative, which means that the secondary shaft is driven in the opposite direction to the rotation of the primary shaft. The movements of the cylinder I! can be controlled by two oblique rods I9a, |9b fixed upon it. u V

.and movable in slides 20a, 20b fast with the outer race of a ball bearing 2|. The inner race of this bearing is movable longitudinally along a groove 22 on a fixed sleeve 23 surrounding the secondary shaft 2. A lever 24 in the form of a fork pivoted II.

on the structure 5 and connected by a pin 25 to the inner race of the bearing 2| provides means for moving the latter along the sleeve 23, so that by means of the slides 20a, 2012 the desired alterations in position of the cylinder I! may be I) achieved.

To overcome the diiiiculties which might ensue from eventual wear of the inner ends of the rods l3 carrying the bearings I 4 and from the friction of these rods in the arms [2, the bearis ings may be mounted in the manner shown in Figures 7 and 8. In this modification each bearing I4 is carried by a cylinder 26 which can rotate in a cup 21 and bears by means of a ball thrust washer 23 on a member 29 integral with 10 V the cup 21 upon which a spring 30 pivoted to the fixed structure 5 acts. The member. 29 is movable in the tension direction of the spring 30 by means of rollers 3! on an inclined plane 32 making with the plane of the disc 9 an angle 0 1| The cylinder i1 is held against the I When the point I which will comply with the conditions regarding friction indicated above. The guides l 6 .by which the orientation of the plane of the bearing I4 is varied are then fixed to the cylinder 26.

What I claim is:

1. A continuously variable change speed gear comprising in combination with a primary shaft and a secondary shaft substantially in line, a disc excentric in relation to the common axis of the said two shafts, coupling means between the disc and the primary shaft to drive the disc about its own axis, coupling means between the disc and the secondary shaft arranged to guide the disc in a movement of circular translation about the common axis and to rotate the secondary shaft at the same angular velocity, and means for modifying the direction of the resultant movement of the disc at some fixed point in its plane so as to produce corresponding variations in the angular speed ratio between the primary and secondary shafts.

2. A continuously variable change speed gear comprising in combination with a primary shaft and a secondary shaft substantially in line, a disc excentric in relation to the common axis of the said two shafts, a universal joint arrangement between the disc and the primary shaft to drive the disc about its own axis, a plate fast with the secondary shaft, means for coupling the disc and plate together so that the disc will follow the rotation of the plate but can rotate on its own axis independently of the plate, and means for modifying the direction of the resultant movement of the disc at some fixed point in its plane so as to produce corresponding variations in the angular speed ratio between the primary and secondary shafts.

3. A continuously variable change speed gear comprising in combination with a primary shaft and a secondary shaft substantially in line, a

disc excentric in relation to the common axis of the said two shafts, coupling means between the disc and the primary shaft to drive the disc about its own axis, coupling means between the disc and the secondary shaft arranged to guide the disc in a movement of circular translation about the common axis and to rotate the secondary shaft at the same angular velocity, ball bearings having their outer races in contact with a face of the disc and with their planes of rotation at an angle to the normal less than the angle of friction between the outer race and the disc face, means for urging the ball bearings against the disc and means for angularly displacing the ball bearings about straight lines each constituted by the intersection of the plane of rotation of the ball bearing with a plane laid through its diameter and perpendicular to the face of the disc so as to produce variations of the resultant direction of movement of the disc corresponding to the desired variations in the angular speed ratio between the primary and secondary shafts.

4. A continuously variable change speed gear comprising in combination with a primary shaft and a secondary shaft substantially in line, a disc excentric in relation to the common axis of the said two shafts, coupling means between the disc and the primary shaft to drive the disc about its own axis, coupling means between the disc and the secondary shaft arranged to guide the disc in a movement of circular translation about the common axis and to rotate the secondary shaft at the same angular velocity, ball bearings having their outer races in contact with a face of the disc with their planes of rotation at an angle to the normal less than the angle of friction between the outer race and the disc face, a fixed structure, supports pivoted to the fixed structure and carrying ball bearings, springs acting on the supports to keep the ball bearings 5 pressed against the disc, and means for angularly displacing the ball bearings about straight lines each constituted by the intersection of the plane of rotation of the ball bearing with a plane laid through its diameter and perpendicular to the 10 face of the disc so as to produce variations of the resultant direction of movement of the disc corresponding to the desired variations in the angular speed ratio between the primary and secondary shafts. 1| 5. A continuously variable change speed gear comprising a combination with a primary shaft and a secondary shaft substantially in line, a disc excentric in relation to the common axis of the said two shafts, coupling means between the 1} disc and the primary shaft to drive the disc. about its own axis, coupling means between the disc and the secondary shaft arranged to guide the disc in a movement of circular translation about the common axis and to rotate the second- .5 ary shaft at the same angular velocity, ball bear- 1 ings having their outer races in contact with a face of the disc and with their planes of rotation at an angle to the normal less than the angle of friction between the outer race and the disc '0 face, a fixed structure, supports pivoted to the fixed structure and carrying ball bearings, springs acting on the supports tokeep the ball bearings pressed against the disc, means by which the bearings can rotate in relation to their respec- {I tive supports about straight lines each constituted by the intersection of the plane of the ball bearing with a plane laid through its diameter and perpendicular to the face of the disc, a pair of parallel arms connected to each of the ball bear- 9 ings and directed perpendicularly to the intersection of the plane of rotation of the ball bearing with the plane of the disc, a movable cylinder embraced by the arms and means for moving the cylinder in the plane containing the common 5 axis of the two shafts and the'axis of the disc to effect changes of orientation of the ball bearings corresponding to the desired variations in the angular speed ratio between the primary and secondary shafts. In

6. A continuously variable speed gear as claimed in claim 5 comprising also a fixed sleeve surrounding the secondary shaft, a ball bearing mounted on the sleeve, means for allowing the inner race of the said ball bearing to slide along ll the sleeve without rotating, oblique guides fixed to the outer race of the ball bearing and arranged parallel to the plane passing through the common axis of the two shafts and the axis of the disc,

rods fast with the movable cylinder and engaging 00.

the oblique guides, and means for moving the ball bearing along the fixed sleeve to effect displacements of the movable cylinder corresponding to the desired variations in the angular speed ratio between the primary and secondary shafts. 05 7. A continuously variable change speed gear comprising in combination a secondary shaft, a. member excentrically fixed thereto, a disc rotatable on the excentrically mounted member about the center of the said member, a primary shaft, 10.

flexible coupling means between the primary shaft and the disc, directional guiding means in contact with a face of the disc and means for varyin the direction of said guiding means.

JEAN ROBERT RAMIN. 7| 

